Cathode Performance of Nanostructured La 1a Sr a Co 1b Fe b O 3x on aC e 0.8 Sm 0.2 O 2 Electrolyte Prepared by Citrate-Nitrate Autocombustion

Nanostructured La1�aSraCo1�bFebO3�x a = 0.3–0.5; b = 0–0.2 and Ce0.8Sm0.2O2 powders were successfully prepared by citratenitrate autocombustion synthesis and were characterized by scanning electron microscopy and X-ray diffraction analysis. Electrochemical impedance spectroscopy measurements on symmetric cells were performed to evaluate the applicability of La1�aSraCo1�bFebO3�x as a cathode material for intermediate temperature solid oxide fuel cells based on Sm doped-ceria electrolytes. Our results demonstrated that strontium has a positive effect while iron shows a slightly negative effect on the interfacial resistance. The effect of the electrode sintering temperature was investigated by varying the temperature from 850 to 1250°C, and the best sintering temperature was found to be 900°C. The best characteristics as cathode at intermediate operating temperatures were found for the composition with a = 0.4 and the minimum iron doping, b = 0.05; at 700°C, an area specific resistance of 0.13 cm 2